1. Field of the Invention
The present invention relates to an integrated photovoltaic modular panel for a curtain wall glass, and in particular, to a photovoltaic panel with amorphous silicon thin film solar cells, concerning with the field of building integrated photovoltaic.
2. Description of the Related Art
Currently, solar cells are connected together by conductive wires and formed a panel with hollow glass or laminated glass. Positive electrodes or negative electrodes on every solar cell of photovoltaic panel are connected in series or parallel. The internal wires are soldered together with an external lead. So the more solar cells to be parallel connected the lower mounting-efficiency is. Regardless of types of electricity supply systems, e.g., a stand-alone system or a networked system, the core of a PV system is a photovoltaic panel made of solar cells. A thin film solar cell does not use the silicon wafer. Instead, it uses a nanometer semiconductor active layer deposited on an inexpensive substrate, such as glass. Thus, the cost of material is greatly reduced. In addition, it has advantage in the manufacturing under lower temperature and can produce a larger size of thin film solar cells.
At present, the photovoltaic panels made from crystal or amorphous silicon solar cells can be used as curtain walls in building material. The peak power of an amorphous silicon solar cell can reach more than 60 Wp. With larger area and better rigidity, the amorphous silicon solar cell, is suitable for making large and extra-large size photovoltaic panels used as photovoltaic curtain wall glass. The photovoltaic panels used as curtain walls in buildings meet the second security standard requirements for its good rigidity and high insulation. In accordance with the industrial standard requirements for battery material, the photovoltaic panel can last for more than 10 years even in a tough environment, such as plus 90 degree or minus 50 degree in Celsius.
A metal frame for supporting solar cells is disclosed in the Chinese invention (application number 200410028002.8), where the solar cells are amorphous silicon solar cells which can accommodate large size, good rigidity and few electrode connection. In addition, the solar cells are easy to form a panel which is arranged at intervals for light transmitting and suits for architecture aesthetics. But one issue has been brought as more photovoltaic panels are used in curtain wall glass. That is, the assembly process can became very complicated and time consuming for the large number of electrodes. The inner structure of the curtain wall glass may be changed and it requires a large space for transporting. In addition, the maintenance is quite difficult, for example, the whole frame needs to be dismantled in order to replace a broken solar cell.